This invention relates to a prism system for use in tricolor separation such as in the field of color television or color photography, where an image obtained through a single objective lens system is separated into images of the three primary colors.
In a television, there have been proposed two types of systems for obtaining image signals. The first system is one in which an image light obtained from a single objective lens system is passed through a striped filter into a single image pick-tube to thereby obtain image signals. In the second system, an image light obtained from a single objective lens system is separated by means of the tricolor separating prism system into three images of the three primary colors. Subsequently, each of the separated images is introduced into a respective image pick-up tube to obtain image signals of each of the three primary colors, which is then followed by photosynthesis, thereby obtaining color image signals. This latter system is used for obtaining a color picture.
There have been proposed various kinds of tricolor separating prism systems for obtaining color images in accordance with this second type of system. These systems, however, suffer from several disadvantages. These disadvantages arise from the fact that the three prisms used each have different shapes, or another subsidiary prism is needed in addition to the three prisms, or air gaps are interposed between each of the adjacent surfaces of the prisms, i.e., the opposing surfaces of the adjoining prisms are not abutting with each other.
These factors in turn increase the complexity of construction of the tricolor separating prism system, thereby resulting in a more costly system.